Airplane wing construction



Aug. 18, 1931. J. v. cRlcHToN AIRPLANE WING CONSTRUCTION 4 Sheets-Sheet.l

Filed Nov. 19, 1929 gn muoz dames'rfabon, zy l j' dtor mm1 Aug. 18,1931.

J. V. CRICHTON AIRPLANE WING CONSTRUCTION Filed Nov. 19, 1929 4Sheets-Sheet4 2 Aug. 18, 1931. J. v. cRlcHToN AIRPLANE WING CONSTRUCTIONFiled Nov. 19, 1929 4 Sheets-Shee4 5 dftoz um,

Aug. 18, 1931. J. v. cRlcHToN AIRPLANE WING CONSTRUCTION Filed NOV. 19,1929 4 Sheets-Sheet. 4

JmesC/iah for?,

d No: 1 m q properly Patented Aug. 18, 1931 UNITED STATES PATENT OFFICEJAMES V. CRICHTON, OF PHILADELPHIA, PENNSYLVANIA, ASSIGNOR OF ONE-HALFT0 KARL SALBERG, 0F PHILADELPHIA, PENNSYLVANIA AIRPLAN E WINGCONSTRUCTION Application iled November 1.9, 1929. Seriall No. 408,213. i

The object of the invention is to provide improvements in airplaneconstruction and more especially in the construction of their Wings.

With the rapid increase in demand and the standardization of airplanes,there has developed as in the case of the automobile a demand fordecrease in cost of production, Without sacrificing in the slightest thenecessary degree ofJ rigidity. That is, while the all-important Wingsmust to all-intents and purposes be sufliciently elastic to prevent theequivalent of brittleness, they must in the general acceptance of theterm be rigid both longitudinally and transversely, with a highcoefficient of safety, to permit the temporary accommodation of excessloads as when abnormally strained by suddenly varying air or Windpressures.

An object of the invention therefore is to provide a construction whichwill insure the maintenance of the proper degree of rigidity,particularly in a longitudinal direction between Wing tips, and at thesame time produce the proportionately necessary transverse anti-iiexingstrength. j

Another object then is to reduce such Wing construction to a system oflfabrication comparable with high speed and low cost construction inother lines vof standardized articles, such construction consistingprimarily in longitudinal girders, connected by positioned transversebracing and such surface members as will provide a relatively unbrokenfoundation for fabric or other covering, or Which can be employedWithout covering in the first instance, or in` sure continuedfunctioning of the Wings if and when such covering may be removed ordestroyed.

','With these and other objects in mind the present invention comprisesfurther details of construction and operation which will be fullybrought out in the following description when read in conjunction withthe accompanying drawings in which Fig. 1 is a schematic viewrepresenting the front elevation of a monoplane in which the oppositelylextending wings are integrally connected to and are in alignment witheach other upon the opposite sides of any desired form of fuselage; Fig.2 is a top plan view of the same, indicating the arrangement of thelongitudinal girders; Fig. 3 is an enlarged transverse sectio on theline 3-3 of Fig. 2; Fig. 4 is'an enlarged fragmentary plan view of aportion of the Wing surface elements; Fig. 5

is a transverse section of the same on the line 55 of Fig. 4; Fig. 6 isan elevational view" of one of the longitudinal girders shown in Fig. 3and substantially as though al section were taken on the line 6-6 ofFig. 3'; Fig. 7 is a similar view of one of the diagonally bracingmembers shownin Fig. 3 and substantially as thoughV taken on the line7-7 of Fig. 3; Fig. 8 is an enlarged transverse section on the lines 8-8of Figs. 6 and 7; Fig. 9 is an enlarged vertical fragmentary sectionsimilar to the forward or left-hand portion of Fig. 3, but showing amodified form of assembly; Fig.`10 is a top plan view of a fragmentaryportion of one of the corrugated surface elementspshown in F-ig. 9;

Referrmg to Figs. 1 to 8,inclusive, the

improved Wmg structure is characterized by the fact that the girders ofFig. 6 and the diagonal braces Yof Fig. 7 extend longitudinally from tipto tip of the oppositely directed wings 1 and 2, that is, transverselyof -the normal line of motion of the airplane body or fuselage 3.Referring' specifically to-Fig. 3, the cross .section of the wingillustrates the latter as being formed of any desired number oflongitudinally extending substantially vertical girders 4, representedin plan in Fig. 6. Each of these girders is t0 be stamped and otherwiseformed by dies from a single blank of sheet metal and essentiallycomprises in the present instance an upper preferably straight edgeportion 5 and a lower edge portion 6, which from a maximum girder widthat the center or junction of the two wings it converges towards theoppositeends into substantially pointed. terminal portions 7. Thisgirder has removed from its body portion excess material to formsubstantially triangular openings 8, so arranged as to provide betweenthe diagonally extending guy sections 9, which zig-zag from upper tolower and lower to upper edge portions from one end to the other of thegirder.

In order to transversely strengthen each of the respective upper andlower edge portions 5 and 6 and the guys 9, each of these portions ofthe girder is preferably corrugated substantially as shown in Fig. 8 toform a central concavo-convex section 10, disposed be tween laterallydeflected edge portions 11, all cooperating and tending to produce localrigidity of the various sections o'f the girder, in order to provide andmaintain a predetermined uniform rigidity of the girder as a whole.

Referring again to Fig. 3, it will be noted that there extends from thelower` edge portion of certain laterally positioned girders to the upperedge portion of intervening girders diagonal braces 12, which from Fig.7 are seen to comprise in themselves a construction similar to the`girders before described. Each o'f these braces comprises a relativelystraight edge portion 13 and oppositely positioned slightly diagonallyextending edge portions 14, said edge portions at their longitudinallyopposite ends being connected by transversely opposite end portions 15,while between said end portions the transversely opposite edge portionsare integrally formed by means of diagonally extending guy sections 16formed between substantially triangular cutout portions 17.. Each ofthese edge, end, and guy sections is also corrugated and provided withlaterally directed edge portions, as shown in Fig. 8 and previouslydescribed.

Also, it will be noted that the opposite edge portions 5 and 6 of thegirders of Fig. 6 and the corresponding edge portions 13 `and 14 of Fig.7 are provided with spaced apertures which are adapted to receive rivets18, as shown in Fig. 3. It willalso be realized that while the centralportion of the braces 12 are diagonally positioned as shown in Fig. 3,they are warped or flexed as Vthey proceed towards their opposite endportions 15, since said end portions connectadjacentV girders at theopposite ends 19 of the wing structure, as shown in Fig. 2, said endslying substantially in a horizontal plane and ing of relatively shallowheight, as indicated at the laterally opposite ends of Figs.`1 and 6. It

`ing diagonally extending should also be noted in passing that the actof flexing these brace members adds to them an increased rigidity andstrength .which they would not otherwise have were they to extend in thesame general direction from end to end.

After the girders 4 and brace 12 areassembled as shown in Fig. 3, thegaps between them are inclosed by means of sheets 20 of relatively thinmetal, each .sheet as indicated in Figs. 4 and 5 being characterized bya central laterally corrugated portion 2l, bounded forwardly andrearwardly by transversely corrugated marginal portions 22, which mergeinto outwardly directed sub stantiallyv parallel flanges 23. Theseflanges are duly perforated and also receive the permanent rivets 18, asillustrated in Fig. 3.

The forward portion of the wings may be inclosed by means of a centrallycors rugated transversely curved section of met` al 24, the oppositemarginal portions 25 of which are longitudinally corrugated andterminate in preferably aligned flanges 26, which are secured to theopposite upper and lower edge portions of the foremost girder. portionmeans of either two converging plates 27 and 28 or by means of a singleplate folded centrally at 29 to form a relatively pronounced trailingedge. This plate or plates may also be corrugated at 30 to affordtransverse stiness, while their divergent marginal portions arecorrugated at 31 and provided with preferably aligned flanges 32 forsecuring to the respective upper and lower edge portions of the rearmostof said girders 4.

Referring to Figs. 9, 10, and 11, a modification of the structurehereinbefore described is illustrated as comprising substantiallyvertical girders 33 which may be similar to the girders 4 illustrated inFig. 6. The upper portions of adjacent girders in this form of thedevice are connected together by brace members of substantial V crosssection, havsides 34, which at their margins merge into nection with theadjacent edge portions of said girders,

perforated and adapted to be secured by rivets 37, welded, or the like,to a similar portion of a similar brace which resembles an inverted V.Thus when completely assembled a substantially X form of bracing isprovided which for some purposes has been found to offer most desirableresults.

ianges 35, for con-` and provided with a central' preferably planeportion 36 which is duly On the other hand, the trailing edge of thewing structure is formed byl The spacesl between the opposite ends ofeach Y of said brace members 34 are spanned and closed by sheets ofrelatively thin metal 38, the central portions of which lie in eithercurved or straight planes which includesor are tangential to theoutermost free edge portions of the girders 33 and intervening braces tothe lower edge girder 45, if the 34. EachA of these sheets 38 iscorrugated along its opposite marginal portions at 39 andthenceoutwardly directedY in substantially parallel flanges 40, which inturn are perforated and secured by means of rivets to similar flangesupon adjacent sheets and to said adjacent edge portions of girders andbraces.

Instead of corrugating the central areas of each of said sheets 38,there may be secured to said areas by rivets, spot-welding, or the like,duly corrugated or folded and flanged stieningmembers 41, substantially,as shown in Figs. 10 to 12 inclusive. Thus, these plates aretransversely stiffened so as not to belly, collapse or appreciablyvibrate under varying wind ressures, and the arrangement of saidstiffemng members may be according to any desired geometric or otherdesign according to the taste or preference of the designing engineer.The forward surfaces of the opposite upper and lower edge portions ofthe foremost girder 33 are connected by` what might be termed halfbraces 42, which are connected to ether by means of parallel flanges 43,well orward of the central portion ofthe adjacent girder. The line o fconnection of these half braces is then connected to the opposite edgeportions of said foremost girder and to the opposite edge portions ofthe respective brace members b means of suitable shaped metal sheets 44,w ich may be formed and stiHened in a manner similar to the sheets 38hereinbefore described.

In Fig. 13, vertical girders 45 are shown as being provided withrearwardly directed marginal flanges 46, it being understood that thelower portion of the wmg is a duplicate of the upper portionillustrated. The under side of each of said flanges is connected to theflange 47 of a downwardly and rearwardly extending brace member 48.Thereafter proceeding preferably from the rear or trailing edge of theplane, a surface sheet of metal 49 is laid upon the combined flanges 46vand 47 and forwardly thereof is bent downwardly to form a diagonalbrace member 50, which terminates in .an angularly directed flange 51,adapted to abut against and be secured to the central portion of thebrace member 48 and to the adjacent flange 51 of a rearwardly andupwardlyextending brace member 50', the lower edge portion 52 of whichAmay be bent forwardly and secured portion 53 of the adjacent lowerportion of the wing structure is other than a substantial duplicate ofits upper portion. It will also be noticed that the rear edge portion ofeach of the plates 49 lies upon and is vduly secured to the combinedflanges 46 and 47 and to the for.- ward portion of the next plate 49rearwardly thereof, where it joins its forwardly extending brace section50, as clearly illustrated in said Fig. 13.

Referring now to Fig. 14, upper and lower surface plates 54 and 55 areused, these plates being connected to adjacent plates by welded orriveted flanfges 56. Substantially the central portion o the oppositelypositioned plates 54 and 55 are connected together by verticallyextending girders 57,

which may be similar in construction to thel girders 4, 33, and 45illustrated in Fig. 6. In order to insure rigidity of this modifiedconstruction, substantially V-shaped brace members 58 are used, similarto the braces 34 in Fig. 9, but manner that their central portions 59may be connected together upon the opposite sides of and to theintervening girder 57. The laterally opposite marginal portion 60 ofthese brace members may be secured in any suitable manner and at anysuitable position to the opposed plates 54 and 55, according to thepreference of the designer.

Fig. 15 illustrates another way in which the surface plates, girders andbraces may be joined so as to provide and insure the maintenance of asubstantially unbroken outer wing surface. .This joint is illustrated inFig. 15 for use in such structures as those shown in Figs. 3 and 8,though it may also be adapted for use with other methods of assembly.Primarily, we have lthe upper portion of a girder 61, upon the oppositesides of which are the upper portions 62 of diagonally extending bracemembers 63. Secured in turn to the opposite sides of said marginalportions 62 of said brace members are the outwardly directed flanges 64of the longitudinally corrugatedmarginal portions 65 of surface plates66 of sheet metal. and of any desired formation. However, it will benoted that in cutting and forming each of said surface plates, alongitudinally extending deression or shoulder 67 is provided at thejunction between the central portion of the plate with the marginalportion 65 and that the marginal portions 62 of the brace mem.

ber 63 are extended outwardly and curved in turned upon their sides,"insuch A opposite direction in order that their edge portions 68 liewithin these depressions 67 and cover the spaces within the marginalplate corrugations 65, thereby providing a substantially smooth andunbroken wing surface as is clearly illustrated.

In conclusion it should be noted that several embodiments of theinvention have been described in order to indicate something of thebreadth of the invention as conceived and perfectedyby the applicant,and that while one for-m may be more ellicient than another undercertain conditions, each form has its advantages and is ada ted for useunder certain characteristiccon 'tions and with certain types ofairplanes.

Referring to Figs. 16 to 19 inclusive, there is shown a constructionwhich provides for they use of sectional longitudinal girde'rs 1ndivergent arms 77,

order to meet condition-s'which arise when the overall tip to tip winglength is so great that it is difficult to handle single girders Withouttheir tending to become bent out of shape or warped during the processof assembly. Otherwise, the resulting structure, after the assembly ofthe several. sections is complete, is the same. 'In this modification ofthe device, a series of girder sections 69 is provided as best shown inFig. 16, each section comprising preferably slightly tapering oppositelypositioned upper and lower marginal portions 70 and 71, connected attheir opposite ends by end sections 72 and 73, obviously of differentlength, while said first sections are preferably connected together bymeans of a transversely extending rib 74 and by oppositely directeddiagonally extending ribs 75, in order to provide an adequately bracedstructure both longitudinally, transversely and diagonally. Each of saidlongitudinal, end and rib sections of the girder is preferably providewith suitable corrgations 76, in order to further stiffen the crosssection of each of said marginal rib sections independently of oneanother, and substantially as indicated in Fig. 8 above described.

Referring to Fig. 18, it will be noted that adjacent girder sections 69may be connected and braced with respect to eachother in any suitablemanner, but for purpose of illustration they are braced substantially ashereinbefore -described and shown in Fig. 9. By this method pairs ofsubstantially V-shaped braces are provided, each brace comprisingconnected together by normally adjacent flattened riveted or boltedsections 78, while the outer free end portions of these brace arms arebent at 79 into parallelism and duly riveted or otherwise securedtogether upon the opposite sides of and to the upper and lower marginalportions 70 of the several sectionswhich are united to form unitgirders.

Finally, the lends of these adjacent parallel brace portions ofneighboring braces terf minate in oppositely extending aligned flanges80, to which may be directly secured surface plates or preferablymetallic sheets 81. Thereafter, in order totransversely Vconnect inrigid relationship the adjacent'edge lportions of each wing section thusformed,

there are provided pairs of angle irons (shown specifically in Fig. 19),comprising normally aligned fianges 82, which duly rest against theouter surface of the cover plates 81 and are secured both to said platesand to the brace fianges 80 therebeneath, as shown in Figs. 16, 17 and18, while said braces also comprise parallel flanges 83, which areadapted to be secured together upon the opposite sides of upwardlyextending parallel marginal portions of said cover plates 81, angularlydeflected intoA parallelism, as

gent portions connected at shown in Figs. 16 and 17. The flanges of eachof said angle irons respectively are connected together by preferablyparallel webs 84, which from Fig. 9 are employed to increase therigidity of said braces.

This construction of wing girder in particular and wing in generalobviously makes for easier assembling, while in such a structure it isobviously more easy than usual to replace defective or damaged sections,whether the sections are girder sections, cover plate sections, orotherwise, while the cost of production is not materially greater thanforms hereinbefore described, and in other ways the structure offershighly desirable commercial advantages towards the end of quantityproduction of highly standardized nature.

' Having thus described my invention, what I claim and desire to protectby Letters Patent of the United States is 1. An airplane wing,oomprisingspaced longitudinally extending girders, diagonally extending braces,and surface plates connecting the marginal portions of said girders,each of said girders being provided with cutout regions forming betweenthem diagonally extending brace portions, the said cutout regionsprogressing in staggered relation between marginal edge portions, saidbraces being corrugated to increase their rigidity.

2. An airplane wing, comprising spaced longitudinally extending girders,diagonally extending braces, and surface plates connecting the marginalportions of said girders, each of said girders being provided withcutout regions forming between them diagonally, extending braceportions, the said cutout regions progressing in staggered relationbetween marginal edge portions, said brace and marginal portions beingcorrugated to provide increased rigidity.

An airplane wing, comprising transversely spaced longitudinallyextending girdilo ers, and intermediate brace Vgirders of ancomprisingdiver-` their free edge portions to corresponding edge portions of saidfirst girders.

4. An airplane wing, comprising transversely spaced longitudinallyextending girders, and pairs of intermediate brace girdgular transversesection ers of V-shaped cross section connected together at theircenters and at their free edge portions being connected to the-edgeportions of said first girders.

5. An airplane wing, comprising transversely spaced` longitudinallyextending girders, pairs of intermediate brace girders of V-shaped crosssection connected together at their centers and at their free edgeportions being connected to the edoe portions of said first girders, andribbed plates connectlao ing said girders and inclosing the spacetherebetween.

6. An airplane wing, comprising transversely spaced longitudinallyextending girders, pairs of intermediate brace girders of V-shaped crosssection connected together at their centers and at their free edge por-`tions being connected to the edge portions of said irst girders, andcorrugated plates secured to, and said plates inclosing the spacebetween said girders.

7. An airplane wing, comprising transversely spaced longitudinallyextending girders, means to transversely brace said girders with respectto one another, and plates connecting said girders and inclosing thespace therebetween, said plates being provided with transversecorrugations to stillen them, and with marginal longitudinalcorrugations merging into flanges normally connected to the marginalportions of said girders.

8. An airplane wing, comprising longitudinally extending sectionalskeleton girders, each section comprising oppositely disposed marginalportions and connecting end portions, means to rigidly secure adjacentgirders fixed with respect to each other in slightly spaced relation,and means to brace the opposite marginal portions of said sections withrespect to each other.

9. An airplane wing, comprising longitudinally extending sectionalskeleton girders, each section comprising oppositely disposed marginalportions and connecting end portions, means to rigidly secure adjacentgirders fixed with respect to each other in slightly spaced relation,and integral transversely extending braces connecting the oppositemarginal portions'of said sections with respect to each other.

10. An airplane wing,comprising longitudinally extending sectionalgirders, each section comprising oppositely disposed margmal portionsand connecting end portions, and means to rigidly secure adjacentgirders together in slightly spaced relation, said girders beingprovided with cutout regions separated by transversely extendinglongitudinally corrugated' braces integrally connected to said marginalportions.

11. A sectional airplane wing, compris.- ing longitudinally extendinggirders in each wing section, diagonally eX- tending braces connecting`the corresponding girders in each wing section, cover plates eX- tendingbetween said girder sections and inclosing the normal upper and lowersides of the space within each wing section, and means connectingadjacent edge portions of said plates and rigidly securing said sectionstogether in slightly spaced relation.

12. A sectional airplane wing, comprising longitudinal girders in eachsection, braces connecting the girders of each section, cover platesextending between and inclosing the normal upper and lower sides of the`space within each wing section, and means connecting adjacent edgeportions of said plates and rigidly securing said sections together.

13. A sectional airplane wing, comprising longitudinal girders in eachsection, braces connecting the girders of each section, coverplatesextending between and inclosing the normal upper and lower sidesof the space within each wing section, the marginal portions of saidplates at the ends of each section being bent to form flanges, andangle-irons connecting adjacent plate flanges together, and respectivelysecured to the body portions of said plates and to said respectivegirder sections.

In testimony whereof I have aliixed my signature.

.JAMES V. CRICHTON.

sectional

